OAKLAND, Calif. -- Grant Balfour likes the number of lopsided wins the Athletics have put together while compiling the second-best record in the majors.

Still, Oakland's closer wouldn't mind getting some more work in save situations.

Balfour pitched a perfect ninth inning to preserve a one-run lead for his second save of the season in a 4-3 victory over the Houston Astros on Tuesday night.

"You're not going to score 10 runs every night, so it's nice to win a one-run ballgame," said Balfour, who has converted 20 straight save opportunities dating to last season. "I've pitched in six games so it's not like I haven't gotten work. We're just trying to play winning baseball."

Reddick drew a two-out walk from reliever Rhiner Cruz (0-1) and took off for second just before Donaldson's hit down the right-field line landed just fair. Houston outfielder Rick Ankiel made a diving attempt but came up short as Reddick raced around the bases.

Eric Sogard added a career-high three hits for the A's, who have won all five games against the Astros this season.

"The name of the game is break point and they did a better job of it than we did," Houston manager Bo Porter said. "We had people on base but could not string the hits together. We're going to start finding ways to win these games."

Sean Doolittle (1-0) gave up Pena's tying home run in the top of the eighth. Oakland improved to 11-0 when scoring four runs or more.

The A's have also won 10 straight games against teams from the AL West, the club's longest single-season stretch since a 13-game streak in 1994.

They did it despite a shaky outing from Griffin.

He struggled with his control early and allowed a career-high four walks, but recovered to retire the final 11 batters he faced before giving way to the bullpen.

"I don't know that I've been more proud of him than today," manager Bob Melvin said. "He was really fighting himself. Then all of a sudden he gives us six innings that we needed. It was quite a turnaround for an outing that we really hadn't seen out of him before."

Pena tied the game at 3 with his solo shot, his first of the season, off Doolittle with two outs in the eighth.

A day after the bombings at the Boston Marathon killed three people and injured more than 170, the A's paid tribute to the victims in the middle of the eighth inning when "Sweet Caroline" played over the loudspeakers while the words "Tonight we are all Bostonians" flashed on the scoreboard.

Game notes
The A's tied a franchise record with three triples. ... Injured Houston OF Fernando Martinez went hitless in six at-bats during the first two games of his rehab assignment. Martinez has been on the disabled list since the start of the season. ... Astros RHP Bud Norris (2-1) carries a 1.96 ERA into the series finale Wednesday afternoon. RHP Bartolo Colon (1-0) goes for Oakland. ... A's INF Scott Sizemore had surgery to repair the torn ACL in his left knee. Sizemore played in just two games after missing all of 2012 with the same injury. ... Oakland 1B Brandon Moss was placed on the paternity list before the game to attend the birth of his son. The A's recalled Peterson from Triple-A Sacramento.